The 3rd Generation Partnership Project (3GPP) is investigating Evolved Packet System (EPS) as a next generation mobile communication system, and studying Home eNodeB (HeNB) as a small base station installed for local cell coverage. Home base stations are base stations designed to serve relatively small geographic areas and are widely deployed at various locations such as homes, offices, shops, and apartments, etc. These home base stations are often used to improve indoor radio coverage, increase throughput, reduce load on macro-cellular networks, and/or provide other benefits for network operators and/or users. Unlike macro base stations that are carefully deployed at specific locations and maintained by network operators, home base stations may be flexibly deployed in an unplanned manner at any location by users.
In 3GPP, local IP access (LIPA) support is defined as a functional requirement for a home base station. LIPA provides IP capable UEs connectivity to a local IP network, such as an IP network inside a home to which the home base station is connected. For example, LIPA enables a UE to connect to another terminal (e.g., a local printer) that is part of the home network without passing through the mobile operator's core network. Conventionally, if a UE wants to connect to a local printer that has no cellular interface, then the UE needs to use a local communication interface such as a wireless LAN. The use of LIPA enables a UE to use a cellular communication interface to communicate with other terminals within the home network because the home base station functions as a gateway between different wireless access technologies.
Once a Packet Data Network (PDN) connection is established for LIPA transmission, data traffic is directed to the home network, and the home base station forwards the data traffic without passing through the mobile operator's core network. However, signaling traffic will continue to traverse the mobile operator's core network. 3GPP has defined certain requirements for LIPA. First, a user may be notified when a home base station provides access to a residential or enterprise IP network. Second, the mobile operator shall be able to configure the home base station to enable or disable local IP access. Third, the mobile operator shall be able to enable or disable local IP access per user subscription per Closed Subscriber Group (CSG). Each home base station is associated with a CSG cell having a CSG identifier. Whether or not a user is permitted to access a CSG cell is determined based on the user's subscription information.
In 3GPP TR 23.829 and TR 23.859, indications to UEs on whether a PDN connection for LIPA traffic can be initiated and/or on the Access Point Name (APN) to request were discussed. Possible solutions are via UE configuration, NAS signaling, or RRC signaling. However, the details of the options are still unclear. In this patent application, detail designs for various possible methods of providing LIPA indication are proposed.